(1) pH gradients in isoelectric focusing, formed by either Ampholine or buffers, have been stabilized. This allows for shortened focusing times for meaningful pI determination over prolonged focusing times, for focusing of SDS-proteins (useful in 2-D macromolecular mapping). Stabilization is indispensable for mechanistic studies. (2) Electrofocusing and isotachophoresis have been shown to be interconvertible. This is important for preparative zone mobilization. (3) Zone mobilization by "constituent displacement" has been successfully tested as another new preparative technique. BIBLIOGRAPHIC REFERENCES: Nguyen, N. Y., Salokangas, A., and Chrambach, A.: Electrofocusing in Natural pH Gradients Formed by Buffers: Gradient Modification and Stability with Time. Anal. Biochem., 77, 311-319, 1977. Caspers, M. L., and Chrambach, A.: Natural pH Gradients Formed by Aminoacids: Ampholyte Distribution, Time Course, Use in Electrofocusing of Protein, Relation to pH Gradients in Isotachophoresis, Separator Effects, Anal. Biochem. 81, 28-39, 1977.